Two important advances in the treatment of renal cancer are gaining acceptance;partial nephrectomy is replacing radical nephrectomy for preserving functioning renal tissue, and minimally invasive surgery is replacing open partial nephrectomy. For both, control of intra-operative renal bleeding is essential. Pluromed has developed a family of Rapid Transition Polymers" (RTPs"), reverse thermosensitive polymers which are liquid at low temperatures and rapidly transition to gel as they warm to body temperature. The aqueous polymer is reversible back to a liquid via cooling and is dissolvable. The Company has developed a new RTP, LeGoo-XL", and a technique, Perfusive Hemostasis", which are used to achieve superior hemostasis during partial nephrectomy. By injecting LeGoo-XL into a segmental branch of the renal artery, blood flow is reversibly interrupted to that renal segment destined for resection while normal flow is maintained to uninvolved s commercialization by performing all of the pre-clinical development required in anticipation of a subsequent clinical trial supporting FDA approval. This includes validation and extension of Phase I results, a comparison of LeGoo-XL to standard arterial clamping techniques, an assessment of the safety and biocompatibility of the polymer, and development of a market-ready injection system. Acute and chronic experiments in pigs and calves will be performed. The Specific Aims of this project are: 1. To verify and extend Phase I results in an acute pig study;2. To compare LeGoo-XL to renal artery clamping in acute and chronic pigs;3. To study pathology in 6 week survival pigs;4. To extend results to a second and larger animal model in an acute calf study;5. To characterize the biocompatibility, toxicity and physiochemistry of LeGoo-XL;6. To develop a market-ready angiographic injector and system 7. To develop an alternative direct renal artery injection technique upon completion ofinimally invasive techniques in this approach by offering superior hemostasis and allowing surgery on one section of the kidney while maintaining normal flow to the remaining renal tissue. PUBLIC HEALTH RELEVANCE: Surgically removing only the morbid part of a diseased kidney instead of removing the entire kidney, nephron- sparing surgery, is beneficial for long-term kidney function. The technical hurdles limiting the adoption of this approach are the ability to control bleeding during the surgery and the need to reduce warm ischemia time. A bloodless field is vital to the success of minimally invasive techniques. LeGoo-XL offers superior hemostasis and the ability to temporarily interrupt flow only to that renal segment destined for resection. This approach has the capability to make the surgeon's job easier and the partial nephrectomy procedure shorter while leading to better renal function and outcomes. It has the potential to enable greater adoption of both the partial nephrectomy approach and the use of minimally invasive techniques in this approach.